興味ある経過を示した早期胃癌の1例―隆起性病変からⅡa＋Ⅱcへの過程

A Case of Early Gastric Cancer Showing an Interesting Course: From protruding lesion to Ⅱa+Ⅱc

　胃の隆起性病変と総称される疾患のなかには，診断学的にさほど困難を感じない典型的なBorrmann Ⅰ型の癌や，粘膜下腫瘍なども含まれるが，鑑別診断のむずかしい症例も数多く存在する．臨床的にも病理学的にも，そのcriteriaがほぼ確立され，比較的診断の容易な腺腫性ポリープも，時にⅠ型の早期癌との鑑別や癌化の問題，またポリポイド癌との鑑別に際して困難を覚えることがある．

　多くの症例が示すように，両者の鑑別や腺腫性ポリープの癌化の診断を確実に下だし得るものは胃生検でしかなく，しかも陽性データのみである．鑑別診断の困難な症例に遭遇し，しかも何らかの原因で胃生検を施行し得なかった場合，残された方法は症例の経過観察しかない．今回は初回検診で良性の隆起性病変と診断され，生検，手術を施行しないまま，6年間の長期観察を行ない，その間に非常に興味のある経過をたどり，最終的にはⅡa＋Ⅱcの早期癌となった症例を経験したので報告する．

　The course of gastric cancer has been often reported in the past, but relatively seldom has it been followed up for a long time. The present case is of interest because it has been under observation for as many as six years, regarded in all probability as an elevated lesion of benign nature, although from the outset it was not completely possible to rule out malignancy, the more so because we could not perform biopsy on account of the patient's refusal. In the interim the growth evoleved from a Ⅱa-like protrusion to cancer of deep penetrating type with features of Ⅱa+Ⅱc.

　The patient, a man aged 60, with no signs and symptoms referrable to the stomach, underwent minute examination of the stomach. Roentgenogram revealed a broad-based, well-defined protrusion, 13 by 10 mm, on the posterior wall of the antrum in the greater curvature side. Biopsy was proposed but was refused. We had to be content with examining him every 4 to 6 months only by x-ray and endoscopy. During the five years since the initial examination the growth remained hardly unaltered in its shape and size. Then, the protrusion grew rapidly low in stature, showing manifest changes suggestive of cancer infiltration into the submucosal layer. Over the years the patient had been urged to undergo biopsy, and after the distinct change of the tumor surgical intervention was advised, but after all it took more than another one year before he consented to the operation. Pathologically, it was papillary adenocarcinoma, as yet in the stage of early cancer of deep penetrating type, its invasion mostly localized in the submucosal layer. Presumably it had remained early cancer of m invasion during the first five years. Perseverance of the examiner and the refusal of the patient led up to an invaluable example of 6-year-long observation of a developing pattern of gastric cancer.